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tree-optimization/103456 - Record only successes from object_sizes_set

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Avoid overwriting osi->changed if object_sizes_set does not update the
size, so that a previous success in the same pass is not overwritten.
This fixes the bootstrap-ubsan build config, which was failing due to
incorrect object size.

gcc/ChangeLog:

	PR tree-optimization/103456
	* tree-object-size.c (merge_object_sizes): Update osi->changed
	only if object_sizes_set succeeded.

gcc/testsuite/ChangeLog:

	PR tree-optimization/103456
	* gcc.dg/ubsan/pr103456.c: New test.

Co-authored-by: Martin Liška <mliska@suse.cz>
Signed-off-by: Siddhesh Poyarekar <siddhesh@gotplt.org>
This commit is contained in:
Siddhesh Poyarekar 2021-12-01 12:58:12 +05:30
parent c177e80609
commit da9386f9a7
2 changed files with 23 additions and 1 deletions
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21
gcc/testsuite/gcc.dg/ubsan/pr103456.c Normal file
View file

@ -0,0 +1,21 @@
/* PR tree-optimization/103456 */
/* { dg-do compile } */
/* { dg-options "-fsanitize=undefined -O -fdump-tree-objsz" } */
static char *multilib_options = "m64/m32";
void
used_arg_t (void)
{
char *q = multilib_options;
for (;;)
{
while (*q)
q++;
while (__builtin_strchr (q, '_') == 0)
while (*q)
q++;
}
}
/* { dg-final { scan-tree-dump-not "maximum object size 0" "objsz1" } } */

3
gcc/tree-object-size.c
View file

@ -854,7 +854,8 @@ merge_object_sizes (struct object_size_info *osi, tree dest, tree orig,
orig_bytes = (offset > orig_bytes)
? HOST_WIDE_INT_0U : orig_bytes - offset;
osi->changed = object_sizes_set (osi, varno, orig_bytes);
if (object_sizes_set (osi, varno, orig_bytes))
osi->changed = true;
return bitmap_bit_p (osi->reexamine, SSA_NAME_VERSION (orig));
}